I did client-facing tech consulting for mobile handset mfgrs. There is often a suite of servers that powers each type of phone too. Whenever they turn those off

I did client-facing tech consulting for mobile handset mfgrs. There is often a suite of servers that powers each type of phone too. Whenever they turn those off, large portions of the phone, or the whole phone, may stop working too. Motorola and Danger were particularly notorious for this.